The present invention relates to a method of and an apparatus for feeding an image recording carrier, and more particularly to a method of and an apparatus for feeding an image recording carrier such as a film by delivering image recording carriers one by one from a stored stack thereof and allowing them to fall by gravity for image recording, the image recording carriers being positioned in a given position at all times to permit images to start being recorded thereon always from a desired position.
There has recently been developed and widely used, particularly in the medical field, a radiation image recording and reproducing system for producing the radiation-transmitted image of an object using a stimulable phosphor material capable of emitting light upon exposure to stimulating rays. When a certain phosphor is exposed to a radiation such as X-rays, .alpha.-rays, .beta.-rays, .gamma.-rays, cathode rays, or ultraviolet rays, the phosphor stores a part of the energy of the radiation. When the phosphor exposed to the radiation is subsequently exposed to stimulating rays such as visible light, the phosphor emits light in proportion to the stored energy of the radiation. The phosphor exhibiting such a property is referred to as a "stimulable phosphor".
In the radiation image recording and reproducing system employing such a stimulable phosphor, the radiation image information of an object such as a human body is stored in a sheet having a layer of stimulable phosphor, and then the stimulable phosphor sheet is scanned with stimulating rays such as a laser beam to cause the stimulable phosphor sheet to emit light representative of the radiation image. The emitted light is then photoelectrically detected to produce an image information signal that is electrically processed for generating image information which is recorded as a visible image on a recording medium such as a photosensitive material or displayed as a visible image on a CRT or the like.
The radiation image information stored in the stimulable phosphor sheet may be permanently recorded on a recording carrier by an image recorder such as an image output laser printer, for example. In the image output laser printer, photographic films stored as a recording material in a magazine are loaded, and taken out one by one by a sheet delivery device such as a suction disk or cup. Thereafter, the film is fed by a feed mechanism such as belts or the like into an image information scanning recording unit. In the image information scanning recording unit, the film is mechanically fed in one direction for auxiliary scanning, while at the same time the film is scanned by a laser beam in a main scanning direction normal to the auxiliary scanning direction, for recording the desired image on the film with an image signal produced from an image reader. After the image has been recorded on the film, the film is then fed into an automatic image developing unit, for example.
In the image reader, a stack of stimulable phosphor sheets is stored in a cassette or a magazine. The stimulable phosphor sheets are taken one by one from the cassette or magazine by a sheet delivery device and a sheet feed mechanism and fed into an image information scanning reading unit, which in turn generates desired image information.
The image recording carrier in the image recorder or the image reader may not necessarily be fed or positioned stably for image recording or reading when it is supplied to an image information scanning recording or reading unit. More specifically, while the image recording carrier is being fed through the feed mechanism or system, it may be shifted or positionally displaced in its transverse direction. It would be highly difficult to accurately and desirably record an image on or read an image from the image recording carrier thus positionally displaced. Where the image recording carrier as it is fed along by the feed system is allowed to fall by gravity and then be gripped by a pair of rollers for image scanning, the leading edge of the image recording carrier may deeply be gripped between the rollers. As a result, the position to start recording or reading an image on the image recording carrier may vary from time to time, and the image may not be stably scanned.
Therefore, it is required to properly position the image recording carrier and fed the same into the image scanning recording or reading unit when the image recording carrier is allowed to fall by gravity for delivery. Various arrangements have been proposed to position the image recording carrier. One example of the proposed schemes is disclosed in Japanese Laid-Open Patent Publication No. 52-79682, for example. In the disclosed scheme, when an image recording carrier as it is fed downwardly is gripped in an inclined condition by feed members such as rollers, the feed members are reversed to position the image recording carrier in a prescribed condition, and thereafter the image recording carrier is gripped and fed by the feed members.
According to the above proposed arrangement, the image recording carrier can be corrected for its positional displacement or deviation under the inclined condition, but cannot be corrected for a transverse positional deviation. Thus, the image recording carrier cannot accurately be positioned in the transverse direction. The aforesaid conventional proposal therefore fails to avoid inaccurate recording of a desired image on the image recording carrier due to a positioning error.